<jats:p>An extract of the aerial parts of Eriostemon australasius Pers.subsp. banksii (A. Cunn. ex Endl .) P.G. Wilson ( Rutaceae ), collected from the Cape York Peninsula, has yielded four novel secondary metabolites. These were identified, by spectroscopic methods, as methyl (E)-4-(3′-methylbut-2′-enyloxy) cinnamate, cis-erioaustralasine [{rel}-1-acetoxymethyl-4,8′-epoxy-3-(1′β,2′β-epoxy-3′β,4′β-para-menth-3′-yl)quinolin-2-one], trans- erioaustralasine [{rel}-1-acetoxymethyl-4,8′-epoxy-3-(1′β,2′β-epoxy-3′β,4′α-para-menth-3′-yl)quinolin-2-one] and furoerioaustralasine [{rel}-2,2′β:4,8′-diepoxy-3-(1′β-hydroxy-3′α,4′α-para-menth-3′-yl) quinoline ]. The structure of cis-erioaustralasine was confirmed by X-ray crystallographic studies. The taxonomic significance of the occurrence of these alkaloids in E. australasius is discussed.